Milk is a product extracted from milkable animals. Currently, it is only possible to milk purring maggots. However, trade caravans will sometimes sell various milks, usually from cows and one- or two-humped camels. Dwarves will not drink "raw" milk - it has to be cooked or turned into cheese.

A milker extracts milk from purring maggots in a Farmer's workshop. Milking other animals is currently not functional (To milk something it has to be carryable, and the only milkable thing you can carry is a purring maggot). However, any milk can be made into cheese.